Roller-to-roller conveyance control apparatus

ABSTRACT

The roller-to-roller conveyance control apparatus includes an amplitude target setting unit that sets an amplitude target value of the tension deviation; an adjustment execution command generation unit that provides a command to adjust the control gain; an adjustment manipulated-variable output unit that outputs an adjustment manipulated variable; a manipulated-variable amplitude determination unit that increases the amplitude of the adjustment manipulated variable until the amplitude of the tension deviation becomes larger than the amplitude target value; and a control-gain calculation device that calculates the control gain from the amplitude and the vibration period of the tension deviation. A tension-shaft speed controller controls a tension-control-shaft motor on the basis of the line speed reference and the adjustment manipulated variable during the adjustment of the control gain.

FIELD

The present invention relates to a roller-to-roller conveyance controlapparatus that conveys a conveyed material, which is made from a rawmaterial, such as metal, resin, or paper, formed in a belt-like orline-like shape, while the material is extended under tension betweenrollers that are individually driven by motors.

BACKGROUND

To convey a conveyed material stably in such a manner that the materialdisposed between two rollers is under a predetermined tension, aroller-to-roller conveyance control apparatus includes speed controllersthat each control the rotational speed of a corresponding roller, andprovides speed references corresponding to the line speed to the speedcontrollers. At the same time, a tension detector detects the tension ofthe conveyed material between the two rollers, and a tension controller,which performs PI (Proportional-Integral) control or PID(Proportional-Integral-Derivative) control such that the tension of theconveyed material agrees with a command value, calculates a compensationvalue and outputs a tension control correction command to the tensioncontrol shaft, which is one of the shafts of the two rollers, as anaddition to the speed reference described above.

Here, it is necessary to set the PI control gain for the tensioncontroller appropriately in order for such a roller-to-roller conveyancecontrol apparatus to convey a conveyed material stably. While theroller-to-roller conveyance control apparatus performs roller-to-rollerconveyance, an operator checks the change in control gain and thecorresponding tension response to adjust the control gain on atrial-and-error basis.

Common types of roller-to-roller conveyance control apparatus oftencannot even convey a conveyed material with the desired conveyingconditions unless the control gain for the tension controller is set toan appropriate value. Hence, in the initial adjustment stage, it isnecessary to check the response of the detected tension value underoperating conditions different from those of a normal operation, such asgentle acceleration/deceleration and a low speed, to make an adjustmentto obtain a control gain with which stable conveyance can be achieved.It is then further necessary to repeat an operation of checking theresponse of the detected tension value under operating conditions closerto those of the normal operation to adjust the control gain such thatthe tension is further stabilized. This means that, because theadjustment of the control gain for a tension controller in aroller-to-roller conveyance control apparatus requires repeated changingof both operating conditions and control gains on a trial-and-errorbasis, it takes a significantly long time and much effort.

A solution to the problem described above is a technique disclosed inPatent Literature 1 that includes a model identification unit andidentifies a control target model of a tension control system; thetechnique then uses the control target model in the repetition of asimulation and evaluation of the response when the control gain ischanged to a candidate value in order to search for an optimal value ofthe control gain using a genetic algorithm and thereby automaticallyadjust the control gain of a tension control calculation unit.

CITATION LIST Patent Literature

Patent Literature 1: Japanese Patent Application Laid-Open No.H10-250888

SUMMARY Technical Problem

To calculate an appropriate control gain, an adjustmentmanipulated-variable amplitude needs to be set appropriately. Theadjustment manipulated-variable amplitude is the amplitude of anadjustment manipulated variable, which generates a periodic vibration intension. If the adjustment manipulated-variable amplitude is small, thetension periodic vibration amplitude, which is the amplitude of aperiodic vibration in tension, becomes small, which results in thetension periodic vibration amplitude being buried in the noise of thetension detector and therefore hinders the calculation of an appropriatecontrol gain. If the adjustment manipulated-variable amplitude is large,there is a risk that a conveyed material ruptures and the apparatus isoverloaded.

Additionally, when the adjustment manipulated-variable amplitude isincreased, depending on the method to increase the adjustmentmanipulated-variable amplitude, the tension periodic vibration amplitudethat has been set may not be achieved even after a long period of time,which results in a failure to complete the automatic adjustment, or thetension periodic vibration amplitude may become too large, which leadsto rupture of a conveyed material or an overload on the apparatus.

The present invention has been achieved in view of the above, and anobject of the present invention is to provide a roller-to-rollerconveyance control apparatus that sets an appropriate adjustmentmanipulated-variable amplitude and automates the adjustment of thecontrol gain.

Solution to Problem

In order to solve the above problems and achieve the object, an aspectof the present invention is a roller-to-roller conveyance controlapparatus that comprises: a speed-shaft roller that is driven by aspeed-control-shaft motor; a tension-shaft roller that is driven by atension-control-shaft motor; a tension detector that detects a tensionof a conveyed material that is conveyed between the speed-shaft rollerand the tension-shaft roller; a line-speed reference setting unit thatsets a line speed reference for the conveyed material; a tension-commandsetting unit that sets a tension command for the conveyed material; atension controller that calculates a tension control correction commandon a basis of a control gain and a tension deviation that is adifference between the tension command and the tension; a speed-shaftspeed controller that controls the speed-control-shaft motor on a basisof the line speed reference; and a tension-shaft speed controller thatcontrols the tension-control-shaft motor on a basis of the line speedreference and the tension control correction command, theroller-to-roller conveyance control apparatus comprises: an amplitudetarget setting unit that sets an amplitude target value of the tensiondeviation; an adjustment execution command generation unit that providesa command to adjust or not to adjust the control gain; an adjustmentmanipulated-variable output unit that outputs an adjustment manipulatedvariable on a basis of the tension deviation during adjustment of thecontrol gain; a manipulated-variable amplitude determination unit thatincreases an amplitude of the adjustment manipulated variable until anamplitude of the tension deviation becomes larger than the amplitudetarget value during adjustment of the control gain; and a control-gaincalculation device that calculates the control gain from the amplitudeand a vibration period of the tension deviation during adjustment of thecontrol gain, wherein the tension-shaft speed controller controls thetension-control-shaft motor on a basis of the line speed reference andthe adjustment manipulated variable during adjustment of the controlgain.

Advantageous Effects of Invention

A roller-to-roller conveyance control apparatus according to the presentinvention produces effects of setting an appropriate adjustmentmanipulated-variable amplitude and automates the adjustment of thecontrol gain.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating an entire view of aroller-to-roller conveyance control apparatus according to first andsecond embodiments of the present invention.

FIG. 2 is a block diagram of a manipulated-variable amplitudedetermination unit according to the first embodiment.

FIG. 3 is a diagram illustrating the behavior of an adjustment executioncommand Ct, an adjustment manipulated variable Vt, a tension Tfb, and atension deviation Te, with an adjustment manipulated-variable amplitudeA fixed to a constant value in the first embodiment.

FIG. 4 is a flowchart illustrating a procedure to increase theadjustment manipulated-variable amplitude A according to the firstembodiment.

FIG. 5 is a diagram illustrating the behavior of the tension deviationTe and the adjustment manipulated variable Vt when the adjustmentmanipulated-variable amplitude A is increased in the first embodiment.

FIG. 6 is a block diagram of a manipulated-variable amplitudedetermination unit according to a second embodiment.

FIG. 7 is a flowchart illustrating a procedure to increase theadjustment manipulated-variable amplitude A according to the secondembodiment.

FIG. 8 is a diagram illustrating the behavior of the tension deviationTe and the adjustment manipulated variable Vt when the adjustmentmanipulated-variable amplitude A is increased in the second embodiment.

FIG. 9 is a block diagram illustrating an entire view of aroller-to-roller conveyance control apparatus according to a thirdembodiment.

FIG. 10 is a block diagram of a manipulated-variable amplitudedetermination unit according to the third embodiment.

FIG. 11 is a flowchart illustrating a procedure to increase theadjustment manipulated-variable amplitude A according to the thirdembodiment.

DESCRIPTION OF EMBODIMENTS

A roller-to-roller conveyance control apparatus according to embodimentsof the present invention will be described below in detail withreference to the drawings. The present invention is not limited to theembodiments.

First Embodiment

FIG. 1 is a block diagram illustrating an entire view of aroller-to-roller conveyance control apparatus 100 according to a firstembodiment of the present invention. The roller-to-roller conveyancecontrol apparatus 100 conveys a conveyed material 1, which is made froma raw material, such as metal, resin, or paper, and is formed in abelt-like or line-like shape. The roller-to-roller conveyance controlapparatus 100 includes a winding roller 2, which winds up the conveyedmaterial 1; a winding motor 3, which drives the winding roller 2; aspeed-shaft speed controller 4, which controls the rotational speed ofthe winding motor 3 such that the conveyed material 1 is wound up at apredetermined line speed; an unwinding roller 5, which unwinds theconveyed material 1; an unwinding motor 6, which drives the unwindingroller 5; a tension-shaft speed controller 7, which controls therotational speed of the unwinding motor 6 such that the conveyedmaterial 1 is unwound at a predetermined line speed; a line-speedreference setting unit 8, which sets a line speed reference for theconveyed material 1; a tension detector 9, which is disposed between thewinding roller 2 and the unwinding roller 5 and detects a tension Tfb ofthe conveyed material 1; a tension-command setting unit 10, which sets atension command Tr for the conveyed material 1; and a tension controller11, which outputs a tension control correction command for correctingthe speed reference to the tension-shaft speed controller 7 such thatthe tension of the conveyed material 1 agrees with the tension commandTr. This enables the conveyed material 1 to be conveyed at apredetermined speed and under a predetermined tension.

The roller-to-roller conveyance control apparatus 100 further includes acontrol-gain calculation device 12, which calculates an appropriatecontrol gain for the tension controller 11; an adjustmentmanipulated-variable output unit 13, which outputs an adjustmentmanipulated variable Vt for the tension-shaft speed controller 7 duringcontrol gain adjustment; a manipulated-variable amplitude determinationunit 14, which determines an adjustment manipulated-variable amplitude Ato be used during the adjustment; an adjustment execution commandgeneration unit 15, which generates an adjustment execution command Ctand provides a command to execute the adjustment of the control gain; anamplitude target setting unit 16, which sets an amplitude target valueAr of a tension periodic vibration for the calculation of the controlgain; adders 41 and 42; and a subtracter 43. Note that Ar is a positivevalue.

The tension controller 11 includes a switch 31 and outputs the tensioncontrol correction command when the switch 31 is on. When the switch 31is off, the tension controller 11 outputs no tension control correctioncommand, causing its output to be zero. The manipulated-variableamplitude determination unit 14 includes a switch 32 and outputs theadjustment manipulated-variable amplitude A when the switch 32 is on.When the switch 32 is off, the manipulated-variable amplitudedetermination unit 14 outputs no adjustment manipulated-variableamplitude A, causing its output to be zero. Since the output of themanipulated-variable amplitude determination unit 14 is zero when theswitch 32 is off, the adjustment manipulated variable Vt, which is theoutput of the adjustment manipulated-variable output unit 13, is alsozero. The output of the tension controller 11 and the output of theadjustment manipulated-variable output unit 13 are added by the adder 41and the result is input to the adder 42.

Before the execution of the adjustment of the control gain, theadjustment execution command Ct is off, and the switches 31 and 32 arealso both off. Subsequently, the adjustment execution command Ct isturned on to start the adjustment of the control gain. During theexecution of the adjustment, the switch 31 is off and the switch 32 ison. Thus, the output of the adder 41 is the adjustment manipulatedvariable Vt during the control gain adjustment. When the adjustmentexecution command Ct is turned off to end the adjustment of the controlgain, the switch 31 is turned on and the switch 32 is turned off;therefore, the output of the adder 41 is the tension control correctioncommand from the tension controller 11. Hence, after the start of theadjustment of the control gain, the adder 42 adds the tension controlcorrection command or the adjustment manipulated variable Vt to the linespeed reference, which is the output of the line-speed reference settingunit 8, and outputs the result to the tension-shaft speed controller 7.That is, during control gain adjustment, the sum of the line speedreference and the adjustment manipulated variable Vt is input to thetension-shaft speed controller 7 and, after the control gain adjustment,the sum of the line speed reference and the tension control correctioncommand is input to the tension-shaft speed controller 7.

FIG. 2 is a block diagram illustrating the manipulated-variableamplitude determination unit 14 according to the first embodiment indetail. The manipulated-variable amplitude determination unit 14according to the first embodiment includes an adjustment mode switchingunit 20, which switches an adjustment mode M; an adjustment mode outputunit 21, which outputs the adjustment mode M set by the adjustment modeswitching unit 20 to the control-gain calculation device 12; an initialmanipulated-variable setting unit 22, which sets an initial value of theadjustment manipulated-variable amplitude A; a counter 23, which countsan elapsed time; a manipulated-variable amplitude time increaser 24,which increases the adjustment manipulated-variable amplitude A inaccordance with a counter value of the counter 23; and amanipulated-variable amplitude storage unit 25, which stores theadjustment manipulated-variable amplitude A. The initialmanipulated-variable setting unit 22, the manipulated-variable amplitudetime increaser 24, and the manipulated-variable amplitude storage unit25 each output the adjustment manipulated-variable amplitude A, which isinput to the adjustment manipulated-variable output unit 13.

The operation of the roller-to-roller conveyance control apparatus 100according to the first embodiment will now be described with referenceto FIG. 1. As illustrated in FIG. 1, the conveyed material 1 is conveyedwhile it is extended between the winding roller 2 and the unwindingroller 5 under a predetermined tension. The line speed for the conveyedmaterial 1 is set by the line-speed reference setting unit 8. The linespeed reference set by the line-speed reference setting unit 8 is sentout to the speed-shaft speed controller 4 and the tension-shaft speedcontroller 7.

The speed-shaft speed controller 4 controls the winding motor 3 suchthat the line speed of the conveyed material 1 is in accordance with theline speed reference set by the line-speed reference setting unit 8.Specifically, the speed-shaft speed controller 4 converts the line speedreference to a converted speed reference that corresponds to therotational speed of the winding motor 3 with consideration given to thediameter and the reduction ratio of the winding roller 2 and performsthe control such that the rotational speed of the winding motor 3 is inaccordance with the converted speed reference. The winding roller 2 isdriven by the winding motor 3 to wind up a certain amount of theconveyed material 1 per unit time.

The tension detector 9, which is disposed between the winding roller 2and the unwinding roller 5, detects the tension Tfb of the conveyedmaterial 1. The tension-command setting unit 10 sets the tension commandTr for the conveyed material 1. When the adjustment execution command Ctgenerated by the adjustment execution command generation unit 15 is off,the tension controller 11 obtains the tension control correctioncommand, which is the sum of a proportional compensation resulting frommultiplication of a tension deviation Te by a proportional gain, and anintegral compensation resulting from multiplication of the tensiondeviation Te by an integral gain and integrating the result; where thetension deviation Te is the difference between the tension Tfb of theconveyed material 1 output by the tension detector 9 and the tensioncommand Tr set by the tension-command setting unit 10. The tensioncontroller 11 sends out the tension control correction command obtainedin the manner described above for the tension-shaft speed controller 7.The tension deviation Te is obtained at the subtracter 43 by subtractingthe tension Tfb from the tension command Tr.

The line-speed reference setting unit 8 sends out the line speedreference to the speed-shaft speed controller 4 and also sends out theline speed reference to the tension-shaft speed controller 7 at the sametime in synchronization. The tension-shaft speed controller 7 receivesthe tension control correction command from the tension controller 11 inaddition to the line speed reference from the line-speed referencesetting unit 8; the tension-shaft speed controller 7 controls theunwinding motor 6 such that the unwinding motor 6 follows a commandresulting from addition of the line speed reference to the tensioncontrol correction command by the adder 42. Specifically, thetension-shaft speed controller 7 converts the command resulting from theaddition of the line speed reference to the tension control correctioncommand to a converted speed reference that corresponds to therotational speed of the unwinding motor 6 with consideration given tothe diameter and the reduction ratio of the unwinding roller 5 andperforms the control such that the rotational speed of the unwindingmotor 6 is in accordance with the converted speed reference. Theunwinding roller 5 is driven by the unwinding motor 6 to unwind acertain amount of the conveyed material 1 per unit time and therebyextends the conveyed material 1 under tension.

It is assumed here that the winding roller 2 is a speed-shaft roller,the winding motor 3 is a speed-control-shaft motor, the unwinding roller5 is a tension-shaft roller, and the unwinding motor 6 is atension-control-shaft motor, although the winding roller 2 may be atension-shaft roller and the unwinding roller 5 may be a speed-shaftroller. Alternatively, the speed-shaft roller and the tension-shaftroller may be intermediate-shaft rollers that perform only the feedingactions between the unwinding roller 5 and the winding roller 2.

The adjustment execution command generation unit 15 turns on theadjustment execution command Ct on the basis of an external instruction,such as operation by an operator. As described above, the tensioncontroller 11 outputs the tension control correction command when theadjustment execution command Ct is off.

When the adjustment execution command Ct is on, the manipulated-variableamplitude determination unit 14 determines the adjustmentmanipulated-variable amplitude A on the basis of the tension deviationTe as described below and sends out the adjustment manipulated-variableamplitude A to the adjustment manipulated-variable output unit 13. Themanipulated-variable amplitude determination unit 14 also sends out theadjustment mode M to the control-gain calculation device 12.

The adjustment manipulated-variable output unit 13 outputs theadjustment manipulated variable Vt on the basis of the adjustmentmanipulated-variable amplitude A received from the manipulated-variableamplitude determination unit 14 and the tension deviation Te output bythe subtracter 43. FIG. 3 is a diagram illustrating the behavior of theadjustment execution command Ct, the adjustment manipulated variable Vt,the tension Tfb, and the tension deviation Te, with the adjustmentmanipulated-variable amplitude A fixed to a constant value. A value ofthe tension command Tr is indicated in the graph of the tension Tfb andsubtracting the tension Tfb from the tension command Tr produces a valueof the tension deviation Te.

Assuming that the adjustment manipulated-variable amplitude A determinedby the manipulated-variable amplitude determination unit 14 isappropriate, the adjustment manipulated variable Vt is generated in amanner described below. When the adjustment execution command Ct isturned on, the adjustment manipulated-variable output unit 13 outputs tothe adder 41 the adjustment manipulated variable Vt, which is a value ofA or −A, whichever works to reduce the tension deviation Te inaccordance with the sign of the tension deviation Te. As describedabove, during the control gain adjustment, the adjustment manipulatedvariable Vt is input to the adder 42 as it is. By switching the sign ofthe adjustment manipulated variable Vt, the tension deviation Tevibrates periodically. The tension deviation Te includes a noisecomponent; thus, switching the sign of the adjustment manipulatedvariable Vt in accordance with the plus and the minus of the tensiondeviation Te causes the adjustment manipulated variable Vt to chatter.Hence, the sign of the adjustment manipulated variable Vt should bedetermined by applying a low-pass filter to the tension deviation Te oron the basis of a signal of the tension deviation Te with hysteresisadded thereto.

The control-gain calculation device 12 calculates a proportional gainand an integral gain that are control gains of the tension controller 11on the basis of the tension deviation Te output by the subtracter 43 andthe adjustment mode M output by the manipulated-variable amplitudedetermination unit 14. When the adjustment mode M transitions to a mode4, which is the mode to calculate the control gains as described below,the control-gain calculation device 12 measures the amplitude and thevibration period of the tension deviation Te. The measurement of theamplitude and the vibration period is continued until the tensiondeviation Te has vibrated a predetermined number of times.

Upon completion of the measurement of the amplitude and the vibrationperiod of the tension deviation Te, the control-gain calculation device12 calculates the proportional gain for the tension controller 11, whichis a value resulting from multiplication of the inverse number of themeasured amplitude by a predetermined constant. The control-gaincalculation device 12 also calculates the integral gain for the tensioncontroller 11, which is a value resulting from division of theproportional gain by an integral time that is a value resulting frommultiplication of the measured vibration period by a predeterminedconstant.

A specific method to calculate the proportional gain and the integralgain may be, for example, to calculate the proportional gain and theintegral gain on the basis of the Ziegler-Nichols' closed loop method.The control gains calculated here are applied as the control gains forthe tension controller 11 to achieve the tension control correspondingto the characteristics of the roller-to-roller conveyance controlapparatus 100 and the conveyed material 1.

The operation of the manipulated-variable amplitude determination unit14 according to the first embodiment will now be described in detailwith reference to FIGS. 1, 2, and 4. FIG. 4 is a flowchart illustratinga procedure to increase the adjustment manipulated-variable amplitude Aaccording to the first embodiment.

The amplitude target setting unit 16 in FIG. 1 sets the amplitude targetvalue Ar of the tension periodic vibration for the calculation of thecontrol gains. The adjustment mode switching unit 20 in FIG. 2 receivesthe adjustment execution command Ct, the amplitude target value Ar, andthe tension deviation Te.

With reference to FIG. 4, in step S101, the adjustment mode switchingunit 20 in FIG. 2 determines whether or not the adjustment executioncommand Ct is on. If it is determined that the adjustment executioncommand Ct is on (step S101: Yes), the adjustment mode switching unit 20sets a mode 1 in the adjustment mode output unit 21; the flowchartproceeds to step S102. The mode 1 is a mode in which an initial value isused as the adjustment manipulated-variable amplitude A. If theadjustment execution command Ct is not on (step S101: No), thedetermination in step S101 is performed again.

In step S102, the adjustment mode switching unit 20 selects the initialmanipulated-variable setting unit 22. The initial manipulated-variablesetting unit 22 outputs, as the adjustment manipulated-variableamplitude A, an initial value that has been set for the adjustmentmanipulated-variable amplitude to the adjustment manipulated-variableoutput unit 13. Here, at the time of initial adjustment, thecharacteristics of the roller-to-roller conveyance control apparatus 100are unknown; thus, an adjustment manipulated-variable amplitude thatcauses the motor to operate at a low speed is set in the initialmanipulated-variable setting unit 22 as the initial value. This canprevent rupture of the conveyed material 1 and an overload on themachine.

After step S102, the flowchart proceeds to step S103. In step S103, theadjustment mode switching unit 20 determines whether or not the tensiondeviation Te is a negative value. If the tension deviation Te is anegative value (step S103: Yes), the adjustment mode switching unit 20sets a mode 2 in the adjustment mode output unit 21; the flowchartproceeds to step S104. The mode 2 is a mode in which the adjustmentmanipulated-variable amplitude A is increased in accordance with theelapsed time. If the tension deviation Te is not a negative value (stepS103: No), the flowchart reverts back to step S102.

In step S104, the adjustment mode switching unit 20 initializes thecounter 23. After step S104, the flowchart proceeds to step S105. Instep S105, the adjustment mode switching unit 20 determines whether ornot the absolute value of the tension deviation Te is larger than theamplitude target value Ar set by the amplitude target setting unit 16.If the absolute value of the tension deviation Te is larger than theamplitude target value Ar (step S105: Yes), the adjustment modeswitching unit 20 sets the mode 4 in the adjustment mode output unit 21;the flowchart proceeds to step S109. If the absolute value of thetension deviation Te is smaller than the amplitude target value Ar (stepS105: No), the flowchart proceeds to step S106.

In step S106, the adjustment mode switching unit 20 selects the counter23, and the counter 23 counts up in accordance with the elapsed time. Instep S107, which is after step S106, the manipulated-variable amplitudetime increaser 24 increases the adjustment manipulated-variableamplitude A in accordance with a counter value of the counter 23. Aspecific method to increase the adjustment manipulated-variableamplitude A may be to have an amount of increase of the amplitude or arate of increase of the amplitude, which is in either case predeterminedper unit time, and to determine the adjustment manipulated-variableamplitude A on the basis of the amount of increase of the amplitude orthe rate of increase of the amplitude, whichever has been predetermined,in accordance with the elapsed time counted by the counter 23. In stepS108, which is after step S107, the manipulated-variable amplitude timeincreaser 24 outputs the adjustment manipulated-variable amplitude A tothe adjustment manipulated-variable output unit 13; the flowchartreverts back to step S105.

In step S109, the adjustment mode switching unit 20 selects themanipulated-variable amplitude storage unit 25, and themanipulated-variable amplitude storage unit 25 stores an adjustmentmanipulated-variable amplitude that causes the absolute value of thetension deviation Te to become larger than the amplitude target value Arfor the first time. In step S110, which is after step S109, themanipulated-variable amplitude storage unit 25 outputs the storedadjustment manipulated-variable amplitude A to the adjustmentmanipulated-variable output unit 13.

The adjustment mode output unit 21 sends out the adjustment mode M thatthe adjustment mode switching unit 20 has switched to to thecontrol-gain calculation device 12. As described above, if the absolutevalue of the tension deviation Te is larger than the amplitude targetvalue Ar (step S105: Yes), the adjustment mode M is switched to the mode4; thus, the control-gain calculation device 12 determines that the modein which the control gains are calculated is present and startsmeasuring the amplitude and the vibration period of the tensiondeviation Te in order to calculate the control gains. Upon completion ofthe measurement of the amplitude and the vibration period of the tensiondeviation Te, the control-gain calculation device 12 calculates thecontrol gains with the amplitude and the vibration period that have beenmeasured. When the control-gain calculation device 12 completes thecalculation of the control gains after the measurement, which continuesuntil the tension deviation Te has vibrated the predetermined number oftimes, the adjustment execution command Ct is turned off. The operationof the control-gain calculation device 12 described here is separatefrom that of the manipulated-variable amplitude determination unit 14and thus is not described in the flowchart in FIG. 4.

After step S110 in FIG. 4, the flowchart proceeds to step S111, in whichthe adjustment mode switching unit 20 determines whether or not theadjustment execution command Ct is off. If the adjustment executioncommand Ct is on (step S111: No), the flowchart reverts back to stepS110, in which the manipulated-variable amplitude storage unit 25outputs the adjustment manipulated-variable amplitude A. If, asdescribed above, the calculation of the control gains is completed andthe adjustment execution command Ct is off (step S111: Yes), theadjustment of the control gains ends.

FIG. 5 is a diagram illustrating the behavior of the tension deviationTe and the adjustment manipulated variable Vt when the adjustmentmanipulated-variable amplitude A is increased by the procedure describedabove. As illustrated in FIG. 5, the adjustment manipulated variable Vtincreases in amplitude in accordance with the elapsed time whilereversing its sign every time the sign of the tension deviation Te ischanged. As the adjustment manipulated-variable amplitude A increases,the amplitude of the tension deviation Te, which is its absolute value,increases. When the amplitude of the tension deviation Te becomes largerthan the amplitude target value Ar, which is set by the amplitude targetsetting unit 16, the adjustment manipulated-variable amplitude A stopsincreasing.

Note that, although the tension detector 9 outputs the tension Tfb inthe description above, the tension of the conveyed material 1 does notnecessarily have to be detected. For example, a structure referred to asa dancer roller, which slides vertically or horizontally, may beprovided in place of the tension detector 9; a predetermined externalforce may be exerted on the dancer roller such that the position of thedancer roller is the equivalence of the tension, and the position of thedancer roller may be detected by a displacement sensor. The descriptionabove can be applied as it is to a configuration that detects a quantityof state having an output that changes depending on the tensionfluctuation of the conveyed material 1, that is, a configuration thatdetects a controlled variable, by replacing the tension command Tr, thetension Tfb, and the tension deviation Te, which are described above,with a controlled-variable command, the controlled variable, and acontrolled-variable deviation.

To calculate the control gain accurately, it is necessary to generate atension periodic vibration having an appropriate amplitude. Since theadjustment manipulated-variable amplitude A that achieves it is unknown,the adjustment manipulated-variable amplitude A is gradually increaseduntil the tension periodic vibration achieves an appropriate amplitudein the first embodiment. If the adjustment manipulated-variableamplitude A is increased by an inappropriate method, a tension periodicvibration amplitude that has been set may not be achieved for a longtime, which may result in failure of completing the adjustment of thecontrol gain.

In contrast, the roller-to-roller conveyance control apparatus 100according to the first embodiment can increase the adjustmentmanipulated-variable amplitude A appropriately until it achieves atension periodic vibration amplitude that is suitable to calculate atension gain, by increasing the adjustment manipulated-variableamplitude A reliably in accordance with the elapsed time. Hence,problems can be avoided such as a failure of completing the adjustmentof the control gain due to the amplitude of the tension deviation Tefailing to achieve an amplitude target for a long time.

Second Embodiment

A roller-to-roller conveyance control apparatus according to a secondembodiment of the present invention has a configuration identical withthat of the roller-to-roller conveyance control apparatus 100 accordingto the first embodiment in FIG. 1, except for the manipulated-variableamplitude determination unit 14.

FIG. 6 is a block diagram illustrating the manipulated-variableamplitude determination unit 14 according to the second embodiment indetail. The manipulated-variable amplitude determination unit 14according to the second embodiment includes an adjustment mode switchingunit 60, which switches the adjustment mode M; an adjustment mode outputunit 61, which outputs the adjustment mode M set by the adjustment modeswitching unit 60 to the control-gain calculation device 12; an initialmanipulated-variable setting unit 62, which sets an initial value of theadjustment manipulated-variable amplitude A; a deviation-reversalmanipulated-variable amplitude increaser 63, which increases theadjustment manipulated-variable amplitude A when the sign of the tensiondeviation Te is reversed; and a manipulated-variable amplitude storageunit 64, which stores the adjustment manipulated-variable amplitude A.The initial manipulated-variable setting unit 62, the deviation-reversalmanipulated-variable amplitude increaser 63, and themanipulated-variable amplitude storage unit 64 each output theadjustment manipulated-variable amplitude A, which is input to theadjustment manipulated-variable output unit 13.

The operation of the manipulated-variable amplitude determination unit14 according to the second embodiment will now be described in detailwith reference to FIGS. 1, 6, and 7. FIG. 7 is a flowchart illustratinga procedure to increase the adjustment manipulated-variable amplitude Aaccording to the second embodiment.

In FIG. 1, the amplitude target setting unit 16 has the amplitude targetvalue Ar of the tension periodic vibration, which is set for thecalculation of the control gains. The adjustment execution command Ct,the tension deviation Te, and the amplitude target value Ar are input tothe adjustment mode switching unit 60.

With reference to FIG. 7, in step S201, the adjustment mode switchingunit 60 in FIG. 6 determines whether or not the adjustment executioncommand Ct is on. If it is determined that the adjustment executioncommand Ct is on (step S201: Yes), the adjustment mode switching unit 60sets the mode 1 in the adjustment mode output unit 61; the flowchartproceeds to step S202. If the adjustment execution command Ct is not on(step S201: No), the determination in step S201 is performed again.

In step S202, the adjustment mode switching unit 60 selects the initialmanipulated-variable setting unit 62. The initial manipulated-variablesetting unit 62 outputs, as the adjustment manipulated-variableamplitude A, an initial value that has been set for the adjustmentmanipulated-variable amplitude to the adjustment manipulated-variableoutput unit 13. Here, at the time of the initial adjustment, thecharacteristics of the roller-to-roller conveyance control apparatus 100are unknown; thus, an adjustment manipulated-variable amplitude thatcauses the motor to operate at a low speed is set in the initialmanipulated-variable setting unit 62 as the initial value. This canprevent rupture of the conveyed material 1 and an overload on themachine.

After step S202, the flowchart proceeds to step S203. In step S203, theadjustment mode switching unit 60 determines whether or not the tensiondeviation Te is a negative value. If the tension deviation Te is anegative value (step S203: Yes), the adjustment mode switching unit 60sets a mode 3 in the adjustment mode output unit 61; the flowchartproceeds to step S204. The mode 3 is a mode in which the adjustmentmanipulated-variable amplitude A is increased when the sign of thetension deviation Te changes. If the tension deviation Te is not anegative value (step S203: No), the flowchart reverts back to step S202.

In step S204, the adjustment mode switching unit 60 determines whetheror not the absolute value of the tension deviation Te is larger than theamplitude target value Ar set by the amplitude target setting unit 16.If the absolute value of the tension deviation Te is larger than theamplitude target value Ar (step S204: Yes), the adjustment modeswitching unit 60 sets the mode 4 in the adjustment mode output unit 61;the flowchart proceeds to step S208. If the absolute value of thetension deviation Te is smaller than the amplitude target value Ar (stepS204: No), the flowchart proceeds to step S205.

In step S205, the adjustment mode switching unit 60 selects thedeviation-reversal manipulated-variable amplitude increaser 63, and thedeviation-reversal manipulated-variable amplitude increaser 63determines whether or not the sign of the tension deviation Te isreversed. If the sign of the tension deviation Te is reversed (stepS205: Yes), the flowchart proceeds to step S206. If the sign of thetension deviation Te is not reversed (step S205: No), the flowchartproceeds to step S207.

In step S206, the deviation-reversal manipulated-variable amplitudeincreaser 63 increases the adjustment manipulated-variable amplitude A.A specific method to increase the adjustment manipulated-variableamplitude A may be to have an amount of increase of the amplitude or arate of increase of the amplitude, which is in either case predeterminedfor use when the sign of the tension deviation Te is reversed, and todetermine the adjustment manipulated-variable amplitude A on the basisof the amount of increase of the amplitude or the rate of increase ofthe amplitude, whichever has been predetermined, when the sign of thetension deviation Te is reversed. In step S207, which is after stepS206, the deviation-reversal manipulated-variable amplitude increaser 63outputs the adjustment manipulated-variable amplitude A to theadjustment manipulated-variable output unit 13; the flowchart revertsback to step S204.

In step S208, the adjustment mode switching unit 60 selects themanipulated-variable amplitude storage unit 64, and themanipulated-variable amplitude storage unit 64 stores the adjustmentmanipulated-variable amplitude A that causes the absolute value of thetension deviation Te to become larger than the amplitude target value Arfor the first time. In step S209, which is after step S208, themanipulated-variable amplitude storage unit 64 outputs the storedadjustment manipulated-variable amplitude A to the adjustmentmanipulated-variable output unit 13.

The adjustment mode output unit 61 sends out the adjustment mode M thatis selected by the adjustment mode switching unit 60 to the control-gaincalculation device 12 in FIG. 1. As described above, if the absolutevalue of the tension deviation Te is larger than the amplitude targetvalue Ar (step S204: Yes), the adjustment mode M is switched to the mode4; thus, the control-gain calculation device 12 determines that the modein which the control gains are calculated is present and startsmeasuring the amplitude and the vibration period of the tensiondeviation Te in order to calculate the control gains. Upon completion ofthe measurement of the amplitude and the vibration period of the tensiondeviation Te, the control-gain calculation device 12 calculates thecontrol gains with the amplitude and the vibration period that have beenmeasured. When the control-gain calculation device 12 completes thecalculation of the control gains after the measurement, which continuesuntil the tension deviation Te has vibrated the predetermined number oftimes, the adjustment execution command Ct is turned off. The operationof the control-gain calculation device 12 described here is separatefrom that of the manipulated-variable amplitude determination unit 14and thus is not described in the flowchart in FIG. 7.

After step S209 in FIG. 7, the flowchart proceeds to step S210, in whichthe adjustment mode switching unit 60 determines whether or not theadjustment execution command Ct is off. If the adjustment executioncommand Ct is on (step S210: No), the flowchart reverts back to stepS209, in which the manipulated-variable amplitude storage unit 64outputs the adjustment manipulated-variable amplitude A. If, asdescribed above, the calculation of the control gains is completed andthe adjustment execution command Ct is off (step S210: Yes), theadjustment of the control gains ends.

FIG. 8 is a diagram illustrating the behavior of the tension deviationTe and the adjustment manipulated variable Vt when the adjustmentmanipulated-variable amplitude A is increased by the procedure describedabove. As illustrated in FIG. 8, the adjustment manipulated variable Vtreverses its sign every time the sign of the tension deviation Te ischanged, and increases in amplitude at every reversal. As the adjustmentmanipulated-variable amplitude A increases, the amplitude of the tensiondeviation Te, which is its absolute value, increases. When the amplitudeof the tension deviation Te becomes larger than the amplitude targetvalue Ar, which is set by the amplitude target setting unit 16, theadjustment manipulated-variable amplitude A stops increasing.

Note that, although the tension detector 9 outputs the tension Tfb inthe description above, the tension of the conveyed material 1 does notnecessarily have to be detected, as in the first embodiment. Theposition of a dancer roller may be detected by a displacement sensor.

In the second embodiment, the adjustment manipulated-variable amplitudeA is also gradually increased until the tension periodic vibrationachieves an appropriate amplitude. If the adjustmentmanipulated-variable amplitude A is increased by an inappropriatemethod, the amplitude of the tension periodic vibration may be increasedexcessively, which may result in rupture of the conveyed material 1 andan overload on the apparatus.

In contrast, the roller-to-roller conveyance control apparatus 100according to the second embodiment increases the adjustmentmanipulated-variable amplitude A while verifying the change of the signof the tension deviation Te; thus, the adjustment manipulated-variableamplitude A can be increased appropriately until it achieves a tensionperiodic vibration amplitude that is suitable to calculate the tensiongains. Hence, the adjustment manipulated-variable amplitude A can beprevented from increasing more than necessary, and thus rupture of theconveyed material 1 and an overload on the apparatus can be avoided.

Third Embodiment

FIG. 9 is a block diagram illustrating an entire view of aroller-to-roller conveyance control apparatus 200 according to a thirdembodiment of the present invention. The roller-to-roller conveyancecontrol apparatus 200 in FIG. 9 has the configuration of theroller-to-roller conveyance control apparatus 100 in FIG. 1, with anaddition of an amplitude threshold setting unit 17, which sets anamplitude threshold At of the tension periodic vibration for switchingmethods to increase the adjustment manipulated-variable amplitude. Theamplitude threshold At is a value larger than zero and smaller than theamplitude target value Ar.

FIG. 10 is a block diagram illustrating in detail themanipulated-variable amplitude determination unit 14 in theroller-to-roller conveyance control apparatus 200 according to the thirdembodiment in FIG. 9. The manipulated-variable amplitude determinationunit 14 according to the third embodiment includes an adjustment modeswitching unit 107, which switches the adjustment mode M; an adjustmentmode output unit 101, which outputs the adjustment mode M set by theadjustment mode switching unit 107 to the control-gain calculationdevice 12; an initial manipulated-variable setting unit 102, which setsan initial value of the adjustment manipulated-variable amplitude A; acounter 103, which counts the elapsed time; a manipulated-variableamplitude time increaser 104, which increases the adjustmentmanipulated-variable amplitude A in accordance with a counter value ofthe counter 103; a deviation-reversal manipulated-variable amplitudeincreaser 105, which increases the adjustment manipulated-variableamplitude A when the sign of the tension deviation Te is reversed; and amanipulated-variable amplitude storage unit 106, which stores theadjustment manipulated-variable amplitude A. The initialmanipulated-variable setting unit 102, the manipulated-variableamplitude time increaser 104, the deviation-reversalmanipulated-variable amplitude increaser 105, and themanipulated-variable amplitude storage unit 106 each output theadjustment manipulated-variable amplitude A, which is input to theadjustment manipulated-variable output unit 13.

The operation of the manipulated-variable amplitude determination unit14 according to the third embodiment will now be described in detailwith reference to FIGS. 9, 10, and 11. FIG. 11 is a flowchartillustrating a procedure to increase the adjustment manipulated-variableamplitude A according to the third embodiment.

In FIG. 9, the amplitude threshold setting unit 17 has the amplitudethreshold At of the tension deviation Te, which is set for switchingbetween the mode 2 and the mode 3. The amplitude target setting unit 16has the amplitude target value Ar of the tension periodic vibration,which is set for the calculation of the control gains. The adjustmentexecution command Ct, the tension deviation Te, the amplitude thresholdAt, and the amplitude target value Ar are input to the adjustment modeswitching unit 107.

With reference to FIG. 11, in step S301, the adjustment mode switchingunit 107 in FIG. 10 determines whether or not the adjustment executioncommand Ct is on. If it is determined that the adjustment executioncommand is on (step S301: Yes), the adjustment mode switching unit 107sets the mode 1 in the adjustment mode output unit 101; the flowchartproceeds to step S302. If the adjustment execution command Ct is not on(step S301: No), the determination in step S301 is performed again.

In step S302, the adjustment mode switching unit 107 selects the initialmanipulated-variable setting unit 102. The initial manipulated-variablesetting unit 102 outputs, as the adjustment manipulated-variableamplitude A, an initial value that has been set for the adjustmentmanipulated-variable amplitude to the adjustment manipulated-variableoutput unit 13. Here, at the time of the initial adjustment, thecharacteristics of the roller-to-roller conveyance control apparatus 200are unknown; thus, an adjustment manipulated-variable amplitude thatcauses the motor to operate at a low speed is set in the initialmanipulated-variable setting unit 102 as the initial value. This canprevent rupture of the conveyed material 1 and an overload on themachine.

After step S302, the flowchart proceeds to step S303. In step S303, theadjustment mode switching unit 107 determines whether or not the tensiondeviation Te is a negative value. If the tension deviation Te is anegative value (step S303: Yes), the adjustment mode switching unit 107sets the mode 2 in the adjustment mode output unit 101; the flowchartproceeds to step S304. The mode 2 is a mode in which the adjustmentmanipulated-variable amplitude A is increased in accordance with theelapsed time. If the tension deviation Te is not a negative value (stepS303: No), the flowchart reverts back to step S302.

In step S304, the adjustment mode switching unit 107 initializes thecounter 103. After step S304, the flowchart proceeds to step S305. Instep S305, the adjustment mode switching unit 107 determines whether ornot the absolute value of the tension deviation Te is larger than theamplitude threshold At set by the amplitude threshold setting unit 17.If the absolute value of the tension deviation Te is larger than theamplitude threshold At (step S305: Yes), the adjustment mode switchingunit 107 sets the mode 3 in the adjustment mode output unit 101; theflowchart proceeds to step S309. If the absolute value of the tensiondeviation Te is smaller than the amplitude threshold At (step S305: No),the flowchart proceeds to step S306.

In step S306, the adjustment mode switching unit 107 selects the counter103, and the counter 103 counts up in accordance with the elapsed time.In step S307, which is after step S306, the manipulated-variableamplitude time increaser 104 increases the adjustmentmanipulated-variable amplitude A in accordance with a counter value ofthe counter 103. A specific method to increase the adjustmentmanipulated-variable amplitude A may be to have an amount of increase ofthe amplitude or a rate of increase of the amplitude, which is in eithercase predetermined per unit time, and to determine the adjustmentmanipulated-variable amplitude A on the basis of the amount of increaseof the amplitude or the rate of increase of the amplitude, whichever hasbeen predetermined, in accordance with the elapsed time counted by thecounter 103. In step S308, which is after step S307, themanipulated-variable amplitude time increaser 104 outputs the adjustmentmanipulated-variable amplitude A to the adjustment manipulated-variableoutput unit 13; the flowchart reverts back to step S305.

In step S309, the adjustment mode switching unit 107 determines whetheror not the absolute value of the tension deviation Te is larger than theamplitude target value Ar set in the amplitude target setting unit 16.If the absolute value of the tension deviation Te is larger than theamplitude target value Ar (step S309: Yes), the adjustment modeswitching unit 107 sets the mode 4 in the adjustment mode output unit101; the flowchart proceeds to step S313. If the absolute value of thetension deviation Te is smaller than the amplitude target value Ar (stepS309: No), the flowchart proceeds to step S310.

In step S310, the adjustment mode switching unit 107 selects thedeviation-reversal manipulated-variable amplitude increaser 105, and thedeviation-reversal manipulated-variable amplitude increaser 105determines whether or not the sign of the tension deviation Te isreversed. If the sign of the tension deviation Te is reversed (stepS310: Yes), the flowchart proceeds to step S311. If the sign of thetension deviation Te is not reversed (step S310: No), the flowchartproceeds to step S312.

In step S311, the deviation-reversal manipulated-variable amplitudeincreaser 105 increases the adjustment manipulated-variable amplitude A.A specific method to increase the adjustment manipulated-variableamplitude A may be to have an amount of increase of the amplitude or arate of increase of the amplitude, which is in either case predeterminedfor use when the sign of the tension deviation Te is reversed, and todetermine the adjust manipulated-variable amplitude A on the basis ofthe amount of increase of the amplitude or the rate of increase of theamplitude, whichever has been predetermined, when the sign of thetension deviation Te is reversed. In step S312, which is after stepS311, the deviation-reversal manipulated-variable amplitude increaser105 outputs the adjustment manipulated-variable amplitude A to theadjustment manipulated-variable output unit 13; the flowchart revertsback to step S309.

In step S313, the adjustment mode switching unit 107 selects themanipulated-variable amplitude storage unit 106, and themanipulated-variable amplitude storage unit 106 stores the adjustmentmanipulated-variable amplitude A that causes the absolute value of thetension deviation Te to become larger than the amplitude target value Arfor the first time. In step S314, which is after step S313, themanipulated-variable amplitude storage unit 106 outputs the storedadjustment manipulated-variable amplitude A to the adjustmentmanipulated-variable output unit 13.

The adjustment mode output unit 101 sends out the adjustment mode M thatis selected by the adjustment mode switching unit 107 to thecontrol-gain calculation device 12 in FIG. 9. As described above, if theabsolute value of the tension deviation Te is larger than the amplitudetarget value Ar (step S309: Yes), the adjustment mode M is switched tothe mode 4; thus, the control-gain calculation device 12 determines thatthe mode in which the control gains are calculated is present and startsmeasuring the amplitude and the vibration period of the tensiondeviation Te in order to calculate the control gains. Upon completion ofthe measurement of the amplitude and the vibration period of the tensiondeviation Te, the control-gain calculation device 12 calculates thecontrol gains with the amplitude and the vibration period that have beenmeasured. When the control-gain calculation device 12 completes thecalculation of the control gains after the measurement, which continuesuntil the tension deviation Te has vibrated the predetermined number oftimes, the adjustment execution command Ct is turned off. The operationof the control-gain calculation device 12 described here is separatefrom that of the manipulated-variable amplitude determination unit 14and thus is not described in the flowchart in FIG. 11.

After step S314 in FIG. 11, the flowchart proceeds to step S315, inwhich the adjustment mode switching unit 107 determines whether or notthe adjustment execution command Ct is off. If the adjustment executioncommand Ct is on (step S315: No), the flowchart reverts back to stepS314, in which the manipulated-variable amplitude storage unit 106outputs the adjustment manipulated-variable amplitude A. If, asdescribed above, the calculation of the control gains is completed andthe adjustment execution command Ct is off (step S315: Yes), theadjustment of the control gains ends.

Note that, although the tension detector 9 outputs the tension Tfb inthe description above, the tension of the conveyed material 1 does notnecessarily have to be detected, as in the first and second embodiments.The position of a dancer roller may be detected by a displacementsensor.

As described above, the roller-to-roller conveyance control apparatus200 according to the third embodiment increases the adjustmentmanipulated-variable amplitude A in accordance with the elapsed time inthe first half of the process of increasing the adjustmentmanipulated-variable amplitude A; thus, problems can be avoided such asa failure of completing the adjustment of the control gain due to theamplitude of the tension deviation Te failing to achieve an amplitudetarget for a long time. The roller-to-roller conveyance controlapparatus 200 according to the third embodiment increases the adjustmentmanipulated-variable amplitude A while verifying the change of the signof the tension deviation Te in the latter half of the process ofincreasing the adjustment manipulated-variable amplitude A; hence, theadjustment manipulated-variable amplitude A can be prevented fromincreasing more than necessary, and thus rupture of the conveyedmaterial 1 and an overload on the device can be avoided.

The configurations illustrated in the embodiments described above areexamples of the content of the present invention. Combination with otherpublicly known techniques is possible, and omitting or changing a partof the configurations is also possible without departing from the spiritof the present invention.

REFERENCE SIGNS LIST

1 conveyed material, 2 winding roller, 3 winding motor, 4 speed-shaftspeed controller, 5 unwinding roller, 6 unwinding motor, 7 tension-shaftspeed controller, 8 line-speed reference setting unit, 9 tensiondetector, 10 tension-command setting unit, 11 tension controller, 12control-gain calculation device, 13 adjustment manipulated-variableoutput unit, 14 manipulated-variable amplitude determination unit, 15adjustment execution command generation unit, 16 amplitude targetsetting unit, 17 amplitude threshold setting unit, 20, 60, and 107adjustment mode switching unit, 21, 61, and 101 adjustment mode outputunit, 22, 62, and 102 initial manipulated-variable setting unit, 23 and103 counter, 24 and 104 manipulated-variable amplitude time increaser,25, 64, and 106 manipulated-variable amplitude storage unit, 31 and 32switch, 41 and 42 adder, 43 subtracter, 63 and 105 deviation-reversalmanipulated-variable amplitude increaser, 100 and 200 roller-to-rollerconveyance control apparatus.

1. A roller-to-roller conveyance control apparatus that comprises: aspeed-shaft roller that is driven by a speed-control-shaft motor; atension-shaft roller that is driven by a tension-control-shaft motor; atension detector that detects a tension of a conveyed material that isconveyed between the speed-shaft roller and the tension-shaft roller; aline-speed reference setting unit that sets a line speed reference forthe conveyed material; a tension-command setting unit that sets atension command for the conveyed material; a tension controller thatcalculates a tension control correction command on a basis of a controlgain and a tension deviation that is a difference between the tensioncommand and the tension; a speed-shaft speed controller that controlsthe speed-control-shaft motor on a basis of the line speed reference;and a tension-shaft speed controller that controls thetension-control-shaft motor on a basis of the line speed reference andthe tension control correction command, the roller-to-roller conveyancecontrol apparatus comprising: an amplitude target setting unit that setsan amplitude target value of the tension deviation; an adjustmentexecution command generation unit that provides a command to adjust ornot to adjust the control gain; an adjustment manipulated-variableoutput unit that outputs an adjustment manipulated variable in such amanner that a sign of the adjustment manipulated variable is reversed ona basis of a sign of the tension deviation during adjustment of thecontrol gain; a manipulated-variable amplitude determination unit thatincreases an amplitude of the adjustment manipulated variable until anamplitude of the tension deviation becomes larger than the amplitudetarget value during adjustment of the control gain; and a control-gaincalculation device that calculates the control gain from the amplitudeand a vibration period of the tension deviation during adjustment of thecontrol gain, wherein the tension-shaft speed controller controls thetension-control-shaft motor on a basis of the line speed reference andthe adjustment manipulated variable during adjustment of the controlgain.
 2. The roller-to-roller conveyance control apparatus according toclaim 1, wherein the manipulated-variable amplitude determination unitincreases the amplitude of the adjustment manipulated variable linearlyin relation to an elapsed time and causes the amplitude of theadjustment manipulated variable to be a constant value after theamplitude of the tension deviation becomes larger than the amplitudetarget value.
 3. A roller-to-roller conveyance control apparatus thatcomprises: a speed-shaft roller that is driven by a speed-control-shaftmotor; a tension-shaft roller that is driven by a tension-control-shaftmotor; a tension detector that detects a tension of a conveyed materialthat is conveyed between the speed-shaft roller and the tension-shaftroller; a line-speed reference setting unit that sets a line speedreference for the conveyed material; a tension-command setting unit thatsets a tension command for the conveyed material; a tension controllerthat calculates a tension control correction command on a basis of acontrol gain and a tension deviation that is a difference between thetension command and the tension; a speed-shaft speed controller thatcontrols the speed-control-shaft motor on a basis of the line speedreference; and a tension-shaft speed controller that controls thetension-control-shaft motor on a basis of the line speed reference andthe tension control correction command, the roller-to-roller conveyancecontrol apparatus comprising: an amplitude target setting unit that setsan amplitude target value of the tension deviation; an adjustmentexecution command generation unit that provides a command to adjust ornot to adjust the control gain; an adjustment manipulated-variableoutput unit that outputs an adjustment manipulated variable on a basisof the tension deviation during adjustment of the control gain; amanipulated-variable amplitude determination unit that increases anamplitude of the adjustment manipulated variable until an amplitude ofthe tension deviation becomes larger than the amplitude target valueduring adjustment of the control gain; a control-gain calculation devicethat calculates the control gain from the amplitude and a vibrationperiod of the tension deviation during adjustment of the control gain;and an amplitude threshold setting unit that sets an amplitude thresholdthat is smaller than the amplitude target value, wherein themanipulated-variable amplitude determination unit increases theamplitude of the adjustment manipulated variable linearly in relation toan elapsed time when the amplitude of the tension deviation is smallerthan the amplitude threshold, increases the amplitude of the adjustmentmanipulated variable every time a sign of the tension deviation changeswhen the amplitude of the tension deviation is larger than the amplitudethreshold and is smaller than the amplitude target value, and causes theamplitude of the adjustment manipulated variable to be a constant valueafter the amplitude of the tension deviation becomes larger than theamplitude target value, and the tension-shaft speed controller controlsthe tension-control-shaft motor on a basis of the line speed referenceand the adjustment manipulated variable during adjustment of the controlgain.
 4. The roller-to-roller conveyance control apparatus according toclaim 1, wherein the tension-shaft speed controller controls thetension-control-shaft motor such that a rotational speed of thetension-control-shaft motor agrees with a rotational speed based on asum of the line speed reference and the adjustment manipulated variablethat increases in amplitude until the amplitude of the tension deviationbecomes larger than the amplitude target value during adjustment of thecontrol gain.
 5. A roller-to-roller conveyance control apparatus thatcomprises: a speed-shaft roller that is driven by a speed-control-shaftmotor; a tension-shaft roller that is driven by a tension-control-shaftmotor; a tension detector that detects a tension of a conveyed materialthat is conveyed between the speed-shaft roller and the tension-shaftroller; a line-speed reference setting unit that sets a line speedreference for the conveyed material; a tension-command setting unit thatsets a tension command for the conveyed material; a tension controllerthat calculates a tension control correction command on a basis of acontrol gain and a tension deviation that is a difference between thetension command and the tension; a speed-shaft speed controller thatcontrols the speed-control-shaft motor on a basis of the line speedreference; and a tension-shaft speed controller that controls thetension-control-shaft motor on a basis of the line speed reference andthe tension control correction command, the roller-to-roller conveyancecontrol apparatus comprising: an amplitude target setting unit that setsan amplitude target value of the tension deviation; an adjustmentexecution command generation unit that provides a command to adjust ornot to adjust the control gain; an adjustment manipulated-variableoutput unit that outputs an adjustment manipulated variable on a basisof the tension deviation during adjustment of the control gain; amanipulated-variable amplitude determination unit that increases anamplitude of the adjustment manipulated variable until an amplitude ofthe tension deviation becomes larger than the amplitude target valueduring adjustment of the control gain; and a control-gain calculationdevice that calculates the control gain from the amplitude and avibration period of the tension deviation during adjustment of thecontrol gain, wherein the manipulated-variable amplitude determinationunit increases the amplitude of the adjustment manipulated variableevery time a sign of the tension deviation changes, and causes theamplitude of the adjustment manipulated variable to be a constant valueafter the amplitude of the tension deviation becomes larger than theamplitude target value, and the tension-shaft speed controller controlsthe tension-control-shaft motor on a basis of the line speed referenceand the adjustment manipulated variable during adjustment of the controlgain.
 6. The roller-to-roller conveyance control apparatus according toclaim 3, wherein the tension-shaft speed controller controls thetension-control-shaft motor such that a rotational speed of thetension-control-shaft motor agrees with a rotational speed based on asum of the line speed reference and the adjustment manipulated variablethat increases in amplitude until the amplitude of the tension deviationbecomes larger than the amplitude target value during adjustment of thecontrol gain.
 7. The roller-to-roller conveyance control apparatusaccording to claim 5, wherein the tension-shaft speed controllercontrols the tension-control-shaft motor such that a rotational speed ofthe tension-control-shaft motor agrees with a rotational speed based ona sum of the line speed reference and the adjustment manipulatedvariable that increases in amplitude until the amplitude of the tensiondeviation becomes larger than the amplitude target value duringadjustment of the control gain.